Water heater and method of making same



Nov. 21, 1939. H. A. THRUSH WATER HEATER AND METHOD OF MAKING SAME FiledJan. 31, 1939 2 Sheets-Sheet l Nov. 21, 1939. H -A. THRUSH 2.1805 7WATER HEATER AND METHOD OF MAKING SAME Filed Jan. 31, 1939 2Sheets-Sheet 2 I \w I lhmll gii llu Patented Nov. 21, 1939 UNITEDSTATES. PATENT oFFicE Homer A. Thrush, Peru, Ind.,- assignor to H. A.

Thrush a 00., Peru, Ind., a corporation of Indiana Application January31, 1939, Serial No. 253,938

5 Claims. (01. 29-1573) I I line from a heating boiler, not shown, andthe This invention relates to heat exchange devices broadly and isparticularly concerned with heaters of the indirect type for use inconnection with hot water or steam boilers for heating the domestic orservice water supply.

The primary object of the invention is to provide a heater or markedsimplicity in construction yet unusually strong and resistant topressure and therefore capable of long life, which may be easilyrendered accessible for cleaning and easily cleaned, and which at thesame time embodies maximumheat exchange efllciency. Accordingly, theimproved heater is of the straight tube type constructed in a mannersuch that all soldered joints are eliminated and in which frictionalresistance to free-flow of water through the tubes as well as throughthe jacket and headers surrounding the tubes is reduced to a minimum.

:0 The invention also contemplates a novel method of making a heater ofthe type specified and which method is conducive to reduction in costs,lightness in weight, long life or service without repairs, and highefliciency in operation.

35 With the foregoing and other objects and advantages in view theinvention consists in the preferred construction and arrangement of theseveral parts which will behereinafter more fully described and claimed.

In the drawings: T

Fig. 1 is a disassembled view in perspective of a heater assemblyconstructed in accordance with the features of the present invention;

Fig.2 is a longitudinal section through the heater of Fig. l with theparts in assembled position;

Fig. 3 is an enlarged detail sectional view showing -the manner in whichthe heater tubes are connected to the end walls of the heater shell or40 jacket; t

Figs. 4 and 5 are, respectively, sectional views taken transverselythrough the end caps at each end of the heater shell looking toward theend of the shell in Fig. 2; and a Fig. 6 is a detailed longitudinalsectional view of the heater shell or jacket. Referring in detail to thedrawings, the im proved heater comprises a main shell or jacketgenerally indicated at 5 which is preferably of 50 cast construction, aswill be more fully hereinafter explained, and is provided with aninternally threaded boss 6 providing an inlet port 641 and another boss1 providing a discharge or v outlet port 1a. Connected to these portsare pipes 55 8 and 9, the pipe 8 representing the circulating pipe 9 thecirculating line to such boiler.

Inserted lengthwise through .the jacket are a plurality of straighttubes In designated in groups Illa, llb, I00 and id according to theflow of water therethrough. These tubes are preferablyof burnishedcopper or material having similar characteristics so as to producemaximum heat transfer efiiciency and at the same time ofier the leastfrictional resistance to the flowof fluid therethrough. As will beunderstood, the domestic or service water supply is passed through thetubes l0.

The one end of the jacket has applied thereto a head or header I 1formed with partitions defining an intake port I: and an outlet ordischarge port IS, the partitions also providing a chamber IS in thehead. The opposite end of the shell or jacket 5 is provided with a heador header i6 formed with a single partition or baiiie wall l'l definingchambers Na and "b which coact with the chamber IE to direct the waterin the desired circulatory path through the tubes.

These heads II and 16 when applied to the opposite ends of the heatercause water or other fluid flowing in through pipe l8' tocirculatethrough tubes Ina into chamber I la, then back through bank of tubeslllb into chamber if, then reversing flow back through tubes I00 intochamber Nb and then returning through tubes "Id and out through pipe I9.

The boiler water or other fluid from which heat is extracted comes inthrough port 6a and flows around the tubes ID to the opposite end of theheater and out through port la.

The heater thus constructed consists essentially of four parts, the castjacket 5, the tubes 10, and the heads or headers H and l6.. 7

The preferred method of making the heater in order to attain the desiredobjects is as follows:

Thejacket 5, as heretofore stated, is preferably a casting. When thecasting is made, the end walls 20 and 2|, note Fig, 6, are cast solidand integral with the jacket, the core disin tegrating duringcasting andafter casting may be extracted through the openings which provide theport's-6a and la. y The tubes III are preferably of burnished copper ormaterial having similar characteristics, as heretofore noted, and tomount these tubes, the end walls 20'and2l are formed with the desirednumber of holes to accommodate a predetermined number of tubes and thelatter are then inserted through these holes and at their opposite endsexpanded radially outwardly into firm engagement with the metal of theend walls which bound the holesor openings. The holes are preferablybored and machined to ensure a snug fit. The ends of the tubes arepreferably projected slightly beyond the end walls 20 and 2|, so thatwhen expansion takes place, the metal of the tubes will be firmlyanchored to the said walls to ensure against endwise displacement. Inthis manner, all soldered joints are eliminated, while at the same timea light, yet strong and rugged job results which is capable of long lifewithout need of repairs and with a minimum of rust or scale formation. I

Any conventional method of expansion may be used. In practice, the tubesare rolled" to bring about the desired expahsion.

The head or headers II and I 6 are also meterably cast, the Jacket andheaders being formed with cooperating bolting-on flanges 22-23 and 24-25to facilitate the mounting operation.

The resultant heater has been found through actual experience'to embodyhigh efliciency and can be manufactured at a relatively low cost.

Despite the low cost of manufacture, the heater possesses greatstrength, ruggedness and safety.

It will be understood that certain changes in construction and designmay be adopted without departing from the spirit or scope of theinvention as defined by the appended claims.

What is claimed is:

1. A water heater comprising a shell body of cast metal having end wallsformed integrally therewith and provided with substantially alignedopenings, a plurality of substantially straight tubes of relatively thingauge material of a heat conductivity considerably higher than that ofthe shell body located in substantially parallel relation with theiropposite ends extending through said openings and expanded intoengagement with the walls of the body around said openings to form afluid-tight joint, said tubes being upset on opposite sides of each ofthe end walls to provide firm contact and anchorage oi the tubes in theend walls, headers at opposite ends of the tubes, said shell beingformed with an inlet port at one extremity and an outlet port at theopposite extremity for the circulation of heating water through theshell and around the tubes, one of said headers being formed withpartitions defining inlet and discharge passages into and from certainof the tubes and an intermediate chamber sealed off from the inlet andoutlet ports operating to reverse the flow of water back to the oppositeheader through other of the tubes, the latter header being formed with apartition defining sealed chambers arranged to reverse the flow of waterfirst back to said first-named chamber and then back to said outletpassage.

2. The method of making a water heater that includes the steps ofcasting a shell body with integral end walls, providing substantiallyaligned openings in said end walls, providing a plurality ofsubstantially straight tubes of relatively-thin gauge material of a heatconductivity considerably higher than that 01 said shell locating saidtubes in substantially parallel relation and extending through saidopenings expanding the ends of said tubes into engagement with the wallsof the body around said openings to form fiuidtight joints therebetween,upsetting said tubes on opposite sides of each of said end walls toprovide firm contact 'and anchorage oi the tubes in the end walls;providing headers at opposite ends of the tubes; providing said shellwith an inlet port at one extremity and an outlet port at the oppositeextremity for the circulation of heating water through the shell andaround the tubes; forming one of said headers with partitions defininginlet and discharge passages into and from certain of the tubes, andwith an intermediate chamber sealed ofi from the inlet and outlet port'soperating to reverse the flow of water back to the opposite headerthrough other of the tubes; and forming said latter header with apartition defining sealed chambers arranged to reverse the fiow of waterfirst back to said first-named chamber and then back to said outletpassage.

3. In a water heater, a metal housing presenting substantially plane endsurfaces comprising end walls integral with said housing and providedwith aligned openings; substantially straight tubes of a material havingcharacteristics similar to those of copper tubing located in saidaligned openings with the opposite ends of said tubes extending intosaid openings and expanded into intimate engagement with the walls 01'the metal around the openings to form a fluid tight joint, said expandedportion 01 the tubes being upset on opposite sides of each of the endwalls to provide solid contact and anchorage of the tubes in the endwalls, headers at opposite ends of the shell for confining water passingthrough the tubes within the housing, said housing being formed withinlet and outlet ports for the circulation of water through the housingand around the tubes, one of said headers being partitioned to defineinlet and discharge passages into and from certain of the tubes; and anintermediate chamber sealed oil from the inlet and outlet portsoperating to reverse the fiow of water back to the opposite headerthrough other of the tubes, the latter header being iormed with apartition defining sealed chambers arranged to reverse the flow of waterfirst back to said first-named chamber and then back to said outletpassage.

4. The method of making a water heater that includes the steps ofcasting a metal housing presenting substantially plane end surfacescomprising end walls integral with said housing, providing said endwalls with aligned openings; locating substantially straight tubes of amaterial having characteristics similar to those of copper tubing insaid aligned openings, extending the opposite ends of said tubes intosaid openings and expanding them into intimate engagement with the wallsoi the metal around they openings to form a fluid tight joint, upsettingsaid expanded portion of the tubes on opposite sides of each end wall toprovide solid contact and anchorage of the tubes in the end walls,applying headers at opposite ends of the shell for confining waterpassing through the tubes within the housing, providing said housingwith inlet and outlet ports for the circulation of water through thehousing and around the tubes, providing one of said headers with apartition to define inlet and discharge passages into and from certainof the tubes and with an intermediate chamber sealed oil from the inletand outlet ports operating to reverse the flow of water back to theopposite header through other of the tubes, and forming the latterheader with a partition defining sealed chambers arranged to reverse theflow of water first back to said first-named chamber and then back tosaid outlet passage.

5. In a water heater, a metal housing presenting substantially plane endsurfaces comprising end walls integral with said housing and providedwith aligned openings; substantially straight tubes of a material havingcharacteristics similar to those of copper tubing located in saidaligned openings with the opposite ends of said tubes extending intosaid openings and expanded into intimate engagement with the walls ofthe metal around the openings to form a fluid tight joint, said expandedportion of the tubes being upset to provide solid contact and anchorageof the tubes in the end walls, headers at opposite ends of the shell forconfining water passing through the tubes within the housing, saidhousing being formed with inlet and outlet of the tubes, the latterheader being formed with a partition defining sealed chambers arrangedto reverse the flow of water first to said first-named 1o chamber andthen to said outlet passage.

HOMER A. 'I'HRUSH.

